The James Webb Space Telescope will collect light approximately 9 times faster than the Hubble Space Telescope. The increased sensitivity will allow scientists to see back to when the first galaxies formed just after the Big Bang. Each of the hexagonal-shaped mirror segments is 1.3 meters (4.26 feet) in diameter, and weighs approximately 20 kilograms or 46 pounds. The completed primary mirror will be over 2.5 times larger than the diameter of the Hubble Space Telescope's primary mirror, which is 2.4 meters in diameter, but will weigh roughly half as much. It will be launched in 2013.